The invention relates to a method of and to an apparatus for making applicators of pledgets and like objects. More particularly, the invention relates to improvements in methods of and in apparatus for making applicators which can be used for insertion of catamenial tampon pledgets. The invention also relates to applicators and parts of applicators which are produced in the improved apparatus by resorting to the improved method.
The following description will deal exclusively, or practically exclusively, with the making of applicators for catamenial tampon pledgets. However, such method and apparatus can be used with equal or similar advantage for the making of applicators or holders of other types of objects, for example, firecrackers.
Commonly owned U.S. Pat. Nos. 4,302,174 to Hinzmann and 4,321,993 to Hinzmann et al. disclose tampon applicators of the type wherein a plastic shell is formed with domed petals at one of its ends and its other end receives a pusher. The pusher is or can be hollow to provide room for a pull thread or cord attached to a pledget which is confined in the shell between the domed petals and the front end of the pusher. These applicators operate satisfactorily and are in widespread use. However, the plastic material of shells and pushers is not soluble in water, e.g., in a body of water in a toilet bowl, so that the disposal of spent applicators presents serious problems. Spent applicators can be found in waste baskets, on streets and on beaches.
In accordance with several prior proposals, the applicators of pledgets are to be made of degradable material which readily disintegrates in water so that a spent applicator can be dropped into and flushed from the bowl of a toilet. The dissolution is rapid and complete so that the applicator is not likely to clog the waste evacuating pipes of toilets. Such prior proposals are disclosed, for example, in U.S. Pat. Nos. 4,412,833 to Wiegner et al. and in 4,453,925 to Decker. A drawback of the patented applicators is that the shells are made from helically convoluted strip stock with helically extending seams. The pushers of these applicators constitute tubes which are made in the same way as the shells, i.e., by winding one or more strips of cardboard or the like around a suitable mandrel and by advancing the thus obtained cylindrical envelope axially to a severing station where the envelope is subdivided into pushers or shells of desired length. One end of each shell is thereupon provided with notches alternating with so-called petals which are domed inwardly in a nextfollowing operation to form a crown which partly or fully closes the respective end of the shell in order to facilitate insertion of the shell into the body cavity prior to expulsion of the pledget by the pusher. The expulsion involves pushing the pledget against the domed petals so that the petals are flexed outwardly and provide an opening for the pledget.
A drawback of the just described applicators is their high cost which is due to the fact that the output of apparatus for making the applicators is very low. Thus, it is necessary to convert one or more strips into a first tubular envelope which is subdivided into discrete pushers, to convert one or more strips into a second tubular envelope which is converted into shells, to provide one end of each discrete shell with a set of cutouts and to dome the thus obtained petals prior to insertion of a pledget and a pusher. Moreover, it is very difficult or plain impossible to make clean cuts (notches) in the end faces of shells which are made by helically winding one or more strips of cardboard or other degradable material because fragments of such material tend to become separated from the petals and then remain in the body cavity of the user of the pledget and cause discomfort and/or infection.
U.S. Pat. No. 4,508,531 to Whitehead discusses the drawbacks of conventional spirally wound shells for use in applicators of pledgets and proposes to make the petals on blanks which are thereupon converted into shells by so-called convolute winding which apparently involves rolling the blank around a suitable mandrel. The cost of making such applicators is still very high since the apparatus which makes convolutely wound shells must receive a supply of prefabricated blanks each of which has a row of petals along one of its edges. A similar proposal is disclosed in the published European patent application Ser. No. 0,115,193.